Process for cleaning sugarbeet pulp

ABSTRACT

A system and corresponding process for cleaning sugarbeet pulp comprising: (a) a tank wherein a sufficient amount of water is added to the pulp to form a first slurry containing about 0.1 to 4 wt-% pulp; (b) a screening apparatus for separating the first slurry into a top portion containing substantially all of the pulp and a bottom portion containing a major proportion of the free foreign material; (c) a mill for reducing the particle size and loosening of adherent foreign material from the pulp; (d) a tank for adding a sufficient amount of water to the top portion to form a second slurry containing about 0.1 to 4 wt-% pulp (e) a screening apparatus for separating the second slurry into a upper portion containing substantially all of the pulp and a minor proportion of the loosened foreign material and a lower portion containing a major proportion of the loosened foreign material; (f) a tank for adding a sufficient amount of water to the upper portion to form a third slurry containing about 0.1 to 4 wt-% pulp; (g) a screening apparatus for separating the third slurry into a overflow portion containing substantially all of the pulp and an underflow portion containing a major proportion of the minor proportion of loosened foreign material; and (h) a pulp press and thermal dryer for removing water from the sugarbeet pulp to form a dried product having less than about 11 wt-% water. This system may optionally include hydrocyclone for removing foreign material from the bottom and lower portions so as to form recyclable water.

FIELD OF THE INVENTION

My invention relates to the washing of vegetable pulp. Morespecifically, my invention relates to the removal of foreign materialfrom sugarbeet pulp by washing the pulp with water so as to form a humandietary food supplement rich in total dietary fiber.

BACKGROUND OF THE INVENTION

The sugarbeet is a form of the common beet "Beta vulgaris" which iscommercially grown in large quantities for the sugar contained in theroot. While dependant upon the particular species and growingconditions, whole natural sugarbeets typically consist of about 75-80wt-% water, 14-20 wt-% sugar, 2-10 wt-% pectic material and minoramounts of other components such as amino acids, minerals, etc.

To extract the sugar component a sugarbeet is washed with water toremove foreign material, sliced into a plurality of pieces, commonlycalled cossettes, to increase the surface area, and contacted with waterunder conditions sufficient to cause a mass transfer of sugar from thesugarbeet cossettes to the water. The resultant products are acommercially valuable sugar containing juice and sugarbeet pulp.

Typically, the sugarbeet pulp is dried and sold as livestock feed.However, recent advances in the processing of sugarbeets has resulted insugarbeet pulp suitable for use as a high-fiber human dietary foodsupplement. This new use of sugarbeet pulp requires that the pulp besubstantially free from foreign material and has created a need for asystem which can efficiently clean sugarbeet pulp so as to render it fitfor human consumption.

SUMMARY OF THE INVENTION

My invention comprises a system for removing free and adherent foreignmaterial from sugarbeet cossettes and sugarbeet pulp comprising: (a) ameans for adding an amount of water to the pulp sufficient to form afirst slurry containing about 0.1 to 4 wt-% pulp; (b) a means forseparating the first slurry into a top portion containing substantiallyall of the pulp and a bottom portion containing a major proportion ofthe free foreign material; (c) a means for mechanically treating thepulp in the top portion so as to reduce the particle size of oversizedpulp pieces and loosen a substantial proportion of the adherent foreignmaterial from the pulp; (d) a means for adding an amount of water to thetop portion sufficient to form a second slurry containing about 0.1 to 4wt-% pulp; (e) a means for separating the second slurry into an upperportion containing substantially all of the pulp and a minor proportionof the loosened foreign material and a lower portion containing a majorproportion of the loosened foreign material; (f) a means for adding anamount of water to the upper portion sufficient to form a third slurrycontaining about 0.1 to 4 wt-% pulp; (g) a means for separating thethird slurry into an overflow portion containing substantially all ofthe pulp and an underflow portion containing a major proportion of theminor proportion of loosened foreign material; and (h) a means forremoving water from the overflow portion to form pulp containing lessthan about 11 wt-% water. The system may optionally include a means forremoving foreign material from the bottom portion and lower portion toform recyclable water.

The resultant dried sugarbeet pulp is fit for human consumption and maybe milled to any desired consistency. The milled pulp may beincorporated, to varying degrees, into many food items such as biscuits,bran mixes, breads, breading, hot and cold breakfast cereals, instantbreakfast mixes, texturized meats, cakes, cake mixes, candy bars,cookies, corn chips, crackers, croutons, doughnuts, fiber supplementtablets, frosting, fruitcake, granola, granola bars, gravy, gravy mixes,muffins, pancake and waffle mixes, pasta, pastries, pie crusts, piefillings, potato chips, pretzels, puddings, salad dressings, sauces,sauce mixes, soup, yogurt, etc.

As utilized herein, "substantially all" refers to at least about 70wt-%.

As utilized herein, "major proportion" refers to at least about 50%wt-%.

As utilized herein, "minor proportion" refers to less than about 50wt-%.

As utilized herein, "substantial portion" refers to at least about 30wt-%.

As utilized herein, the term "sugarbeet pulp" refers to sugarbeet fromwhich a substantial proportion of sugar has been extracted.

As utilized herein, the term "free foreign material" refers to allextraneous matter such as clay, rocks, sand, silt, soil, etc. present asseparate particles in sugarbeet pulp.

As utilized herein, the term "adherent foreign material" refers to allextraneous matter such as clay, rocks, sand, silt, soil, etc. which aresecurely coupled to the sugarbeet pulp.

As utilized herein, the term "recycled water" refers to water,previously used to remove foreign material from sugarbeet pulp, whichhas had an amount of foreign material removed such that the water caneffectively remove additional foreign material from sugarbeet pulp.

As utilized herein, the term "screen-size opening" refers to the minimumclear space between the edges of the openings in a screen.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic drawing of a first embodiment of the presentinvention.

FIG. 1A is a front view of one embodiment of tank 20 with a portionthereof broken away.

FIG. 1B is a side view of one embodiment of screening apparatus 30 witha portion thereof broken away.

FIG. 1C is a side view of one embodiment of mill 40 with a portionthereof broken away.

FIG. 1D is a front view of one embodiment of tank 50 with a portionthereof broken away.

FIG. 1E is a side view of one embodiment of screening apparatus 60 witha portion thereof broken away.

FIG. 1F is a front view of one embodiment of tank 70 with a portionthereof broken away.

FIG. 1G is a side view of one embodiment of screening apparatus 80 witha portion thereof broken away.

FIG. 1H is a front view of one embodiment of tank 100 with a portionthereof broken away.

FIG. 1I is a cross-sectional front view of one embodiment of separatingapparatus 130.

FIG. 1J is a front view of one embodiment of tank 140 with a portionthereof broken away.

FIG. 1K is a front view of one embodiment of tank 150 with a portionthereof broken away.

FIG. 2 is a schematic drawing of a second embodiment of the presentinvention.

FIG. 2A is a front view of one embodiment of tank 220 with a portionthereof broken away.

FIG. 2B is a side view of one embodiment of screening apparatus 230 witha portion thereof broken away.

FIG. 2C is a side view of one embodiment of mill 240 with a portionthereof broken away.

FIG. 2D is a front view of one embodiment of agitator 250 with a portionthereof broken away.

FIG. 2E is a side view of one embodiment of screening apparatus 260 witha portion thereof broken away.

FIG. 2F is a front view of one embodiment of tank 270 with a portionthereof broken away.

FIG. 2G is a side view of one embodiment of screening apparatus 280 witha portion thereof broken away.

FIG. 2H is a front view of one embodiment of tank 300 with a portionthereof broken away.

FIG. 2I is a cross-sectional front view of one embodiment of separatingapparatus 330.

FIG. 2J is a front view of one embodiment of tank 340 with a portionthereof broken away.

FIG. 2K is a front view of one embodiment of tank 350 with a portionthereof broken away.

DETAILED DESCRIPTION OF THE INVENTION INCLUDING A BEST MODE FIG. 1

Referring generally to FIGS. 1 and 1A-1K, wet sugarbeet pulp fromsugarbeet diffuser 10 and sufficient water, preferably recycled water141 from holding tank 140, are added to tank 20 through a pulp inletorifice 22 and a water inlet orifice 23 respectively to form a firstslurry 21 containing about 0.1 to 4 wt-%, preferably about 1 to 4 wt-%,sugarbeet pulp. The first slurry 21 is agitated in tank 20 by anysuitable means, such as an impeller 25, to ensure a uniform slurry. Theuniform first slurry 21 is then conveyed by suitable means, such as pump29, from tank 20, through first slurry outlet orifice 24 to screeningapparatus 30 wherein first slurry 21 is separated into a top portion 31acontaining substantially all of the sugarbeet pulp and a bottom portion31b containing substantially all of the water and a major proportion ofthe free foreign material. The bottom portion 31b may be discarded orconveyed to recycle tank 100 for recycling but is preferably employed atsome other unrelated stage in the sugarbeet processing plant. The topportion 31a is combined with sufficient fresh and/or recycled water 141,preferably recycled water 141 from holding tank 140, to form a flowableslurry 41 which is conveyed to mill 40. In mill 40 the particle size ofthe sugarbeet pulp in slurry 41 is reduced and a substantial proportionof adherent foreign material loosened from the sugarbeet pulp. Theflowable slurry 41 is then conveyed by suitable means from mill 40 intotank 50 through slurry inlet port 52 along with sufficient water,preferably underflow 81b from screening apparatus 80, added throughwater inlet port 53, to form a second slurry 51 containing about 0.1-4wt-%, preferably about 0.5-2 wt-%, sugarbeet pulp. The second slurry 51is agitated in tank 50 by any suitable means, such as impeller 55, toensure a uniform slurry. The uniform second slurry 51 is then conveyedby suitable means, such as pump 59, from tank 50, through second slurryoutlet port 54 and into screening apparatus 60 wherein the second slurry51 is separated into an upper portion 61a containing substantially allof the disintegrated sugarbeet pulp and a lower portion 61b containingsubstantially all of the water and a major proportion of the adherentforeign material which has been loosened from the sugarbeet pulp.

The lower portion 61b may be discarded or employed at some otherunrelated stage in the sugarbeet processing plant, but is preferablyconveyed to recycle tank 100 for recycling. The upper portion 61a isconveyed from screening apparatus 60 through outlet port 63 and intotank 70, through upper portion inlet opening 72 wherein sufficientwater, preferably a mixture of recycled water 141 from holding tank 140and fresh water from an outside source (not shown), are added throughwater inlet opening 73 to form a third slurry 71 containing about 0.1-4wt-%, preferably about 0.5-2 wt-%, sugarbeet pulp. The third slurry 71is agitated in tank 70 by any suitable means such as impeller 75, toensure a uniform slurry. The uniform third slurry 71 is then conveyed bysuitable means, such as pump 79, from tank 70, through third slurryoutlet opening 74 and into screening apparatus 80 through inlet opening82 wherein the third slurry 71 is separated into an overflow portion 81acontaining ubstantially all of the disintegrated sugarbeet pulp and anunderflow portion 81b containing substantially all of the water and amajor proportion of the remaining loosened adherent foreign material.The underflow portion 81b may be discarded, conveyed to recycle tank 100or employed at some other unrelated stage in the sugarbeet processingplant, but is preferably conveyed directly to tank 50 through waterinlet port 53 for formation of the second slurry 51. The overflowportion 81a is conveyed through outlet opening 83 to pulp press 90 forthe removal of a substantial portion of the water therefrom. The pressedpulp is then conveyed to a thermal dryer (not shown) for evaporation ofsufficient water to form sugarbeet pulp having less than about 11 wt-%water. The water pressed from the sugarbeet pulp in pulp press 90 may bediscarded, employed at some other unrelated stage in the sugarbeetprocessing plant, or conveyed to recycle tank 100 for recycling, but ispreferably conveyed directly to holding tank 140 through inlet orifice142 for use as recycled water 141 in the present process.

The water 101 in recycle tank 100 is conveyed from recycle tank 100through outlet orifice 104 and to a separating means, such ashydrocyclone 130, by suitable means, such as pump 109. The water 101 isseparated in hydrocyclone 130 through outlet orifice 104 and to aseparating means, such as hydrocyclone 130, into a recyclable portion141 which is conveyed by suitable means to holding tank 140 from whichit can be reused and a waste portion 151, containing substantially allof the foreign material, which is conveyed by suitable means into wastetank 150 through inlet port 152 for temporary storage until it can bedisposed of by conventional means.

FIG. 2

Referring generally to FIGS. 2 and 2A-2K, wet sugarbeet pulp fromsugarbeet diffuser 210 and sufficient water, preferably recycled water341 from holding tank 340, are added to tank 220 through a pulp inletorifice 222 and a water inlet orifice 223 respectively to form a firstslurry 221 containing about 0.1 to 4 wt-%, preferably about 1 to 4 wt-%,sugarbeet pulp. The first slurry 221 is agitated in tank 220 by anysuitable means, such as an impeller 225, to ensure a uniform slurry. Theuniform first slurry 221 is then conveyed by suitable means, such aspump 229, from tank 220, through first slurry outlet orifice 224 toscreening apparatus 230 wherein first slurry 221 is separated into a topportion 231a containing substantially all of the sugarbeet pulp and abottom portion 231b containing substantially all of the water and amajor proportion of the free foreign material. The bottom portion 231bmay be discarded or conveyed to recycle tank 300 for recycling but ispreferably employed at some other unrelated stage in the sugarbeetprocessing plant. The top portion 231a is combined with sufficient freshand/or recycled water 341, preferably recycled water 341 from holdingtank 340, to form a flowable slurry 241 which is conveyed to mill 240.In mill 240 the particle size of the sugarbeet pulp in slurry 241 isreduced, a substantial proportion of adherent foreign material loosenedfrom the sugarbeet pulp, and sufficient water, preferably recycled water341 from holding tank 340, is added to the top portion 231a to form asecond slurry 251 containing about 0.1-4 wt-%, preferably about 0.5-2wt-%, sugarbeet pulp. The second slurry 251 is then conveyed, bysuitable means, to agitator 250 wherein the second slurry 251 isagitated so as to loosen a substantial portion of the adherent foreignmaterial which is still attached to the pulp after exiting mill 240. Thesecond slurry 251 is then conveyed, by suitable means, to screeningapparatus 260 wherein the second slurry 251 is separated into an upperportion 261a containing substantially all of the disintegrated sugarbeetpulp and a lower portion 261b containing substantially all of the waterand a major proportion of the foreign material loosened from thesugarbeet pulp by mill 240 and agitator 250.

The lower portion 261b may be discarded or employed at some otherunrelated stage in the sugarbeet processing plant, but is preferablyconveyed to recycle tank 300 for recycling. The upper portion 261a isconveyed from screening apparatus 260 into tank 270 through upperportion inlet opening 272, wherein sufficient water, preferably amixture of recycled water 341 from holding tank 340 and fresh water froman outside source (not shown), are added through water inlet opening 273to form a third slurry 271 containing about 0.1-4 wt-%, preferably about0.5-2 wt-%, sugarbeet pulp. The third slurry 271 is agitated in tank 270by any suitable means such as impeller 275, to ensure a uniform slurry.The uniform third slurry 271 is then conveyed by suitable means, such aspump 279, from tank 270, through third slurry outlet opening 274 andinto screening apparatus 280 wherein the third slurry 271 is separatedinto an overflow portion 281a containing substantially all of thedisintegrated sugarbeet pulp and an underflow portion 281b containingsubstantially all of the water and a major proportion of the remainingloosened adherent foreign material. The underflow portion 281b may bediscarded or conveyed to recycle tank 300 or employed at some otherunrelated stage in the sugarbeet processing plant, but is preferablyconveyed directly into tank 250 through water inlet port 253 forformation of the second slurry 251. The overflow portion 281a isconveyed to pulp press 290 for the removal of a substantial portion ofthe water therefrom. The pressed pulp is then conveyed to a thermaldryer (not shown) for evaporation of sufficient water to form sugarbeetpulp having less than about 11 wt-% water. The water pressed from thesugarbeet pulp in pulp press 290 may be discarded, employed at someother unrelated stage in the sugarbeet processing plant, or conveyed torecycle tank 300 for recycling, but is preferably conveyed directly toholding tank 340 through inlet orifice 342 for use as recycled water 341in the present process.

The water 301 in recycle tank 300 is conveyed from recycle tank 300through outlet orifice 304 and to a separating means, such ashydrocyclone 330, by suitable means, such as pump 309. The water 301 isseparated in hydrocyclone 430 into a recycle portion 341 which isconveyed by suitable means to holding tank 340 through inlet orifice 342from which it can be recycled back into the present system, and a wasteportion 351, containing substantially all of the foreign material, whichis conveyed by suitable means into waste tank 350 through inlet port 352for temporary storage until it can be disposed of by conventional means.

Diffusers 10 and 210 are conventional equipment used in sugarbeetprocessing plants to extract the sucrose from sugarbeet cossettes bycontacting the sugarbeet cossettes with a diffusion liquid, typicallywater. The diffusion liquid exits the diffuser as a sugar-exhaustedjuice while the cossettes exit the diffuser as sugar-poor pulp. For adetailed discussion of the function, design, selection and use ofsugarbeet diffusers, see McGinnis, Beet-Sugar Technology, 3rd Ed., pp.119-154.

Tanks 20, 220, 50, 70, and 270 respectively, each have at least onewater inlet 23, 223, 53, 73 and 273 respectively for allowing theintroduction of recycled and/or fresh water; a pulp inlet 22, 222, 52,72, and 272 respectively, for allowing the introduction of sugarbeetpulp; a means for slurrying the water and pulp retained therein to forma substantially uniform slurry 25, 225, 55, 75 and 275 respectively; andan outlet 24, 224, 54, 74 and 274 respectively, for allowing thedischarge of slurry. The water and pulp may be slurried in anyconvenient manner such as by a rotating impellor, proper placement ofthe inlets, pneumatic bubbling, etc. For a detailed discussion on thefunction, design, selection and use of process, storage and agitationvessels, see Perry and Chilton, Chemical Engineers Handbook, 5th Ed.,pp. 6-85 to 6-89 and. pp. 21-4 to 21-10, both sections of which arehereby incorporated by reference.

Tanks 100, 300, 140, 340, 150 and 350 retain water laden with foreignmaterial (100, 300) recyclable water (140, 340), and waste water (150,350). The function, design, selection and use of these tanks is similarto tanks 20, 220, 50, 70 and 270 as discussed above with the exceptionsthat an agitation means is unnecessary and pulp is not intentionallyadded to the tank.

Pumps 29, 229, 59, 79, 279, 109 and 309 convey first slurry (25, 225),second slurry (55), third slurry (75, 275), and water laden with foreignmaterial (105, 305). For a detailed discussion on the function, design,selection and use of pumps, see Perry and Chilton, Chemical EngineersHandbook, 5th Ed., pp. 6-3 to 6-36, and Lambeck, Raymond P., HydraulicPumps and Motors, pp. 7-60, both of which are hereby incorporated byreference.

Separating screens 30, 230, 60, 260, 80, and 280 separate first slurry(30, 230), second slurry (60, 260), and third slurry (80, 280) into twoportions, one portion containing substantially all the sugarbeet pulpand a second portion containing substantially all of the water and amajor proportion of the free and loosened foreign material in theslurry. To achieve an effective separation between pulp and foreignmaterial, screens 35, 235, and 365 preferably have screen-size openingsof about 0.060 to 0.13 inches, with a screen-size opening of about 0.06to 0.10 inches being most preferred. Screen-size openings smaller thanabout 0.060 inches tend to significantly increase the amount of foreignmaterial remaining in the sugarbeet pulp while screen-size openings ofgreater than about 0.13 inches tend to significantly increase the amountof sugarbeet pulp passing through the screen with the foreign material.To achieve an effective separation between pulp and foreign material,screens 65, 85 and 285 preferably have screen-size openings of about0.006 to 0.02 inches, with a screen-size opening of about 0.006 to 0.01inches being most preferred. Screen-size openings smaller than about0.006 tend to significantly increase the amount of foreign materialremaining in the sugarbeet pulp while screen-size openings of greaterthan about 0.02 inches tend to significantly increase the amount ofsugarbeet pulp passing through the screen with the foreign material. Thescreening apparatus may be any of the conventional screens includingspecifically but not exclusively static screens such as 30, 230, 60, 80and 280, and vibrating screens such as 260. For a detailed discussion onthe functioning, design, selection and use of separating screens, seePerry and Chilton, Chemical Engineers Handbook, 5th Ed., pp. 21-39 to21-45, which is hereby incorporated by reference.

Mills 40 and 240 effect a size reduction of sugarbeet pulp and loosenadherent foreign material from the sugarbeet pulp. For a detaileddiscussion on the function, design, selection and use of mills, seePerry and Chilton, Chemical Engineers Handbook, 5th Ed., pp. 8-35 to8-42, which is hereby incorporated by reference.

Agitator 250 agitates the second slurry 51 and 251 to loosen adherentforeign material from the disintegrated sugarbeet pulp. The amount ofadherent foreign material loosened varies dependent upon, among otherfactors, dwell time, type of agitator and agitation rate. One type ofagitator capable of providing effective loosening of adherent foreignmaterial is the attrition scrubber unit sold by the Denver EquipmentDivision of Joy Mfg. For a detailed discussion on the function, design,selection and use of agitators, see Perry and Chilton, ChemicalEngineers Handbook, 5th Ed., pp. 19-3 to 19-23.

Pulp presses 90 and 290 squeeze water from the pulp by mechanicallyforcing the pulp into continuously smaller volumes. The resultantpressed pulp typically contains from about 65 to 85 wt-% water. Thepress 90 and 290 commonly employed in sugarbeet plants is the twinscrew, horizontal pulp press available from various manufacturers. For adetailed discussion on the function, design, selection and use of pulppresses, see McGinnis, Beet-Sugar Technology, 3rd Ed., pp. 625-633 andPerry and Chilton, Chemical Engineers Handbook, 5th Ed., pp. 19-101 to19-104, both of which are hereby incorporated by reference.

Separator 130 and 330 is preferably a cyclone separator. Cycloneseparators are a well defined group of devices which can separate amulti-component feedstream into a light fraction and a heavy fraction bysubjecting the feedstream to centrifugal force and a pressure gradient.Generally, a cyclone separator is an inverted, right circular frustum ofa cone having an outlet 133 and 333 at the top, an outlet 134 and 334 atthe bottom, a tangential inlet 132 and 332 near the top and an outletpipe 135 and 335 extending into the inner cavity 136 of the separator130 and 330 from the top outlet 133 and 333 to prevent the feedstreamfrom passing directly from the tangential inlet 132 and 332 to the topoutlet 133 and 333.

In operation, a multi-component feedstream is introduced into thecyclone separator 130 and 330 through the tangential inlet 132 and 332whereupon it develops a rotating vortical motion. The vortex thus formeddevelops a centrifugal force which acts to throw the heavier portion ofthe feedstream radially toward the sidewall 137 and 337 of the separator13d. The feed stream follows a downward spiral adjacent the sidewall 137and 337 of the separator 130 and 330 until it approaches the bottom atwhich time the lighter portion of the feedstream separates from theheavier portion of the feedstream to form an inner vortex which movesupward, in a tight spiral, through the top outlet 133 and 333 of thecyclone separator 130 and 330. The heavier portion of the feedstreamcontinues spiralling downward until it passes out of the cycloneseparator 130 and 330 through the bottom outlet 134 and 334.

A detailed discussion of the function, design, selection and use ofcyclone separators may be found in Perry and Chilton, Chemical EngineersHandbook, 5th Ed., pp. 20-81 through 20-87.

A major portion of the adherent foreign material is loosened from thepulp by mill 40, 240 and agitator 251. However, significant portions ofthe adherent foreign material are also loosened by the remainder of thesystem, in particular tanks 20, 220, 50, 70 and 270.

Since the resultant dried sugarbeet pulp is to be used as a humandietary food supplement, the equipment is preferably constructed of amaterial which does not taint the flavor of the resultant driedsugarbeet pulp and or significantly reduces microbial growth in thesystem. To achieve these ends, the preferred material of construction isstainless steel.

The specification and Drawings are presented to aid in a complete,nonlimiting understanding of the invention. Since many variations andembodiments of the invention can be made without departing from thespirit and scope of the invention, the invention resides in the claimshereinafter appended.

I claim:
 1. A method of seperating free and adherent foreign materialfrom vegetable pulp, comprising the steps of:(a) adding an amount ofwater to the foreign material containing pulp sufficient to form a firstslurry containing about 0.1 to 4 wt-% pulp; (b) separating the firstslurry into a top portion containing substantially all of the pulp and abottom portion containing a major proportion of the free foreignmaterial; (c) reducing the particle size of and loosening adherentforeign material from the pulp in the top portion; (d) adding an amountof water to the top portion sufficient to form a second slurrycontaining about 0.1 to 4 wt-% pulp; (e) separating the second slurryinto an upper portion containing substantially all of the pulp and aminor proportion of the loosened foreign material and a lower portioncontaining a major proportion of the loosened foreign material; (f)adding an amount of water to the upper portion sufficient to form athird slurry containing about 0.1 to 4 wt-% pulp; (g) separating thethird slurry into an overflow portion containing substantially all ofthe pulp and a minor proportion of the loosened foreign material and anunderflow portion containing a major proportion of the loosened foreignmaterial; and (h) removing water from the overflow portion to form pulpcontaining less than about 11 wt-% water.
 2. The method of claim 1further comprising the step of removing foreign material from the bottomportion and lower portion so as to form recycle water.
 3. The method ofclaim 2 wherein at least a portion of the water added to the pulp toform the first slurry is recycle water.
 4. The method of claim 2 whereinthe first slurry is separated by a first screening apparatus havingabout 0.06 to 0.13 inch screen-size openings.
 5. The method of claim 4wherein the first screening apparatus has about 0.06 to 0.10 inchscreen-size openings.
 6. The method of claim 4 wherein the firstscreening apparatus is a static screen.
 7. The method of claim 2 whereinthe particle size of the pulp is reduced by a mill.
 8. The method ofclaim 7 wherein the mill is a disintegrator.
 9. The method of claim 2wherein at least a portion of the water added to the top portion to formthe second slurry is recycle water.
 10. The method of claim 2 whereinthe second slurry is separated by a second screening apparatus havingabout 0.06 to 0.13 inch screen-size openings.
 11. The method of claim 10wherein the second screening apparatus is a static screen.
 12. Themethod of claim 10 wherein the second screening apparatus is a vibratingscreen.
 13. The method of claim 2 wherein at least a portion of thewater added to the upper portion to form the third slurry is recyclewater.
 14. The method of claim 2 wherein the third slurry is separatedby a third screening apparatus having about 0.006 to 0.02 inchscreen-size openings.
 15. The method of claim 14 wherein the thirdscreening apparatus is a static screen.
 16. The method of claim 2wherein water is removed from the overflow portion by a press and athermal dryer in series.
 17. The method of claim 16 wherein the presscomprises a screw press.
 18. The method of claim 2 wherein foreignmaterial is removed from the bottom and lower portions by ahydrocyclone.
 19. The method of claim 1 wherein foreign material isremoved from the bottom, lower and underflow portions to form recyclewater.
 20. The method of claim 16, wherein the water removed from theoverflow portion by the press is added to the recycle water.
 21. Themethod of claim 1 wherein the particle size of the pulp in the topportion is reduced prior to formation of the second slurry.